Long Term Evolution (LTE) technology supports a Frequency Division Duplexing (FDD) mode and a TDD mode. FIG. 1 is a schematic diagram illustrating the frame structure of a TDD system. In the TDD system, the length of each radio frame is 10 ms, and each radio frame is divided into two half frames with the length of 5 ms. Each half frame contains 8 time slots with the length of 0.5 ms and 3 special domains. The 3 special domains contain a Downlink Pilot Time Slot (DwPTS), a Guard Partition (GP) and an Uplink Pilot Time Slot (UpPTS). The total length of the 3 special domains is 1 ms. Each subframe is composed of two continuous time slots, that is, the kth subframe contains a time slot 2k and a time slot 2k+1. The TDD system supports 7 types of uplink and downlink configurations, as shown in Table 1. In Table 1, “D” indicates downlink subframes, “U” indicates uplink subframes, and “S” indicates special subframes containing the above 3 special domains.
TABLE 1Table 1, uplink and downlink configuration of LTE TDDIndexSwitchingof con-pointsubframe indexfigurationperiod012345678905msDSUUUDSUUU15msDSUUDDSUUD25msDSUDDDSUDD310msDSUUUDDDDD410msDSUUDDDDDD510msDSUDDDDDDD610msDSUUUDSUUD
In theory, each cell may use a TDD uplink and downlink configuration different from that used by an adjacent cell to adapt the change of traffic. Actually, if adjacent cells use different TDD uplink and downlink configurations, uplink transmission and downlink transmission of the adjacent cells will be interfered with each other, which will be illustrated hereinafter referring to FIG. 2.
FIG. 2 is a schematic diagram illustrating interference between adjacent cells using different TDD uplink and downlink configurations in the prior art. In FIG. 2, a subframe 3 of macro evolved Nobe B (eNB) is an uplink subframe,
the subframe 3 of Low Power Node (LPN) is a downlink subframe, and thus these subframes are called conflict subframes in the present application, such as subframes 3 203 and 8 208. Subframes 0, 1, 4, 5, 6 and 9 of macro eNB are downlink subframes, the subframes 0, 1, 4, 5, 6 and 9 of LPN are also downlink subframes, and thus these subframes are called non-conflict subframes in the present application. In the conflict subframes, on one hand, the downlink data transmission of LPN interferes with uplink data that is transmitted to the macro eNB by all terminals of macro eNB, and the closer the distance from the LPN to the macro eNB is, the more serious the interference is; on the other hand, the uplink data that is transmitted by the terminals of macro eNB will seriously interfere with the downlink data received at terminals of LPN that are closer to the terminals of macro eNB.
FIG. 2 illustrates the interference between uplink transmission and downlink transmission of adjacent cell by taking the macro eNB and the LPN as an example, and the interference also occurs between other adjacent cells.
In order to avoid the interference between uplink transmission and downlink transmission of adjacent cells in the TDD system, the adjacent cells use the same TDD uplink and downlink configuration at present. However, uplink traffic and downlink traffic of different cells are unbalanced, that is, a certain cell has more uplink traffic and adjacent cells of the cell have more downlink traffic. In this case, different cells need to use different TDD uplink and downlink configurations to meet respective traffic requirements. The above two kinds of requirements are inconsistent, and thus a problem to be solved by the present application is to use different TDD uplink and downlink configurations in different cells, so as to meet the requirements of variation of uplink and downlink traffic, and avoid serious interference between uplink transmission and downlink transmission of adjacent cells.